The goal of interventions like wearing face coverings and social distancing is to reduce the effective reproduction number — the number of new infections caused in the real world by each infected person — below 1.0. MELISSA SUE GERRITS/GETTY IMAGES
Using our Covid-19 Simulator, we estimated that a lockdown of four to six weeks could substantially decrease Covid-19 in most states. Following such an intense period of sacrifice, it would be possible to reopen colleges and universities, and likely other schools and businesses, with firm masking and distancing policies to contain transmission.
